nodejs实现随机uuid

UUID是一个由4个连字号(-)将32个字节长的字符串分隔后生成的字符串，总共36个字节长。比如：29be34ed-1860-47e8-9a52-7707578a2b98

function randomUUID() {
    const hexDigits = "0123456789abcdef";
    const s = [];
    for (let i = 0; i < 36; i++) {
      s[i] = hexDigits.substr(Math.floor(Math.random() * 0x10), 1);
    }
    s[14] = "4"; // bits 12-15 of the time_hi_and_version field to 0010
    s[19] = hexDigits.substr((s[19] & 0x3) | 0x8, 1); // bits 6-7 of the clock_seq_hi_and_reserved to 01
    s[8] = s[13] = s[18] = s[23] = "-";

    const uuid = s.join("");
    return uuid;
}